Some sliding door apparatuses have a structure in which a door body that slides with respect to an opening part is moved in a depth direction immediately before the door body closes the opening part. Such sliding door apparatuses can improve interior airtightness.
For example, JP62-069579U discloses a door apparatus including a rail horizontally extended in such a manner that the rail is inclined at an angle of 45 degrees, a hanger having a door roller mechanism with a pair of rollers, and a door body hanging from the rail by means of the hanger. In this door apparatus, one roller of the pair of rollers is supported on an upper end surface of the rail, while the other roller of the pair of rollers is supported on an inclined side surface of the rail. A recess is formed in a part of the upper end surface of the rail. Thus, immediately before the door body closes the opening part, the roller on the upper end surface of the rail falls down the recess, so that the door body is moved downward and in the depth direction. Thus, the door body comes close to the opening part.
In addition, for example, JP2537064Z discloses a door apparatus including a horizontally extended rail, a hanger having a roller that rolls on the rail, and a door body hanging from the rail by a hanger. In this door apparatus, a recess, which is concaved downward and toward an opening part, is formed in a part of the rail. Thus, immediately before the door body closes the opening part, the roller on the rail falls down the recess, so that the door body is moved downward and in the depth direction. Thus, the door body comes close to the opening part.
In a door apparatus of this type, when the door body is opened, it is necessary to cause the roller fitted in the recess to roll on an inclined part of the recess so as to escape from the recess. This operation requires considerable force. Thus, the door apparatus of Patent Document 1 is equipped with an assisting mechanism that assists the opening operation by making use of an elastic force of a coil spring that is compressed as the door body comes close to the closed state.